Several international studies have documented substantial levels of sexual risk behaviors and high rates of STI and HIV amongst long-distance truck drivers living in diverse settings including India, Bangladesh, South Africa and Thailand. In the United States, while it is known that STI and HIV cases are frequently concentrated around major transportation routes, less is known regarding specific HIV/STI risk behaviors and HIV/STI prevalence amongst the over 3 million truck drivers in this country. Among the few U.S. studies addressing this topic, a recent Florida-based study found that approximately 30% of the long-haul trucker population studied had frequent sexual intercourse with multiple partners while they were on the road but few used condoms. In addition, knowledge deficits and misconceptions regarding heterosexual HIV transmission were common among study participants. Thus based on what little data are available, the need for HIV/STI prevention intervention in this population in the U.S. appears to be considerable. To date, essentially all of the domestic and international studies performed on truck drivers have recruited study participants from truck stops or businesses catering to truckers. This application will seek to design a sustainable risk assessment and screening protocol in collaboration with several large freight lines in the U.S. with the goal of informing an HIV/STI intervention for this population. Our study will propose to address the following specific aims: 1) To perform focus groups and in-depth interviews based on the constructs of the transtheoretical model with long-haul truck drivers to guide development of both a behavioral risk assessment instrument and an acceptable HIV/STI screening protocol for long-haul truckers; 2) To perform in-depth interviews with trucking industry executives to determine barriers to routine HIV/STI assessment and screening of their employees; 3) To adapt existing theory-based measures of behavioral risk based on focus group data from long-haul truck drivers so as to reflect the attitudes and culture of this understudied population; 4) To estimate the prevalence of key sexual risk behaviors and examine the predictors of those prevalence rates; and 5) To determine the prevalence of HIV, N. gonorrhoeae, and C. trachomatis, in long-haul truck drivers. [unreadable] [unreadable]